九江—瑞昌主-余震的波速比变化初探
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摘要
根据流动台网对九江-瑞昌地震序列的定位结果,采用单台波速比方法,计算各流动台的波速比变化,得出以下结果:①各台波速比存在一定幅度的变化,但变化形态不一致,这可能与震源区应力调整有关;九江台和武蛟台的波速比在2006年4月下中旬至6月中旬这段时间较明显处于低值区间,相应的主余震的M-T图显示余震活动在该段时间内强度和频度有较明显的增强。②沿以武蛟和狮子洞两台连线的NW走向的波速比最小,结合主-余震北西向较优势分布和震源机制解的其中一组NW向节面,推断北西向断裂可能是九江一瑞昌5.7级主震的发震构造。
According to the seismic localization result from the mobile observation arrays,the Vp/VS ratios can be calculated by using single station method.The calculation results are shown as follows: ①The Vp/VS ratios from mobile observation arrays vary in a certain extent,but their change tendency is different,this may be relevant to stress adjustment in the seismogenic faults.From mid-April to mid-June in 2006,the Vp/VS ratios of JUJ and WUJ stations are in the lower level,and the seismic activities show obviously enhancement during that time according to the aftershocks M-T chart.②The Vp/VS ratios in the northwest direction along the WUJ to SZD are least.So it is concluded that the fault with northwest strike may be the seismogenic structure of the Jiujiang-Ruichang M5.7 earthquake with the north-west predominated spatial distribution of the earthquake sequence and NW zone from focal mechanism solutions.
According to the seismic localization result from the mobile observation arrays,the Vp/VS ratios can be calculated by using single station method.The calculation results are shown as follows: ①The Vp/VS ratios from mobile observation arrays vary in a certain extent,but their change tendency is different,this may be relevant to stress adjustment in the seismogenic faults.From mid-April to mid-June in 2006,the Vp/VS ratios of JUJ and WUJ stations are in the lower level,and the seismic activities show obviously enhancement during that time according to the aftershocks M-T chart.②The Vp/VS ratios in the northwest direction along the WUJ to SZD are least.So it is concluded that the fault with northwest strike may be the seismogenic structure of the Jiujiang-Ruichang M5.7 earthquake with the north-west predominated spatial distribution of the earthquake sequence and NW zone from focal mechanism solutions.
引文
[1]冯德益.地震波速异常[M].北京:地震出版社,1981.
[2]蔡静观,梅蓉,张喜玲,等.从高波速比试论云南丽江7级地震的孕震模式[J].地震研究,1999,22(2):122-129.
[3]蔡静观,张嘉玲.丽江、宁蒗强震前波速比时空演化过程和数值分析[J].中国地震,1999,15(1):82-91.
[4]蔡静观,张嘉玲,李永莉.云南地区波速比异常图像的南北差异[J].西北地震学报,1999,21(4):363-369.
[5]周焕鹏.渤海海域波速比异常研究及地震危险性分析[J].地震研究,1995,18(3):252-257.
[6]蔡静观.波速比计算中的不确定因素和在地震预报中的应用[J].地震研究,2000,23(1):51-56.
[7]吕坚,高建华,赵爱平,等.九江-瑞昌5.7级地震序列重新定位与震源机制解[J].防灾减灾工程学报,2006,26(增刊):83-87.
[2]蔡静观,梅蓉,张喜玲,等.从高波速比试论云南丽江7级地震的孕震模式[J].地震研究,1999,22(2):122-129.
[3]蔡静观,张嘉玲.丽江、宁蒗强震前波速比时空演化过程和数值分析[J].中国地震,1999,15(1):82-91.
[4]蔡静观,张嘉玲,李永莉.云南地区波速比异常图像的南北差异[J].西北地震学报,1999,21(4):363-369.
[5]周焕鹏.渤海海域波速比异常研究及地震危险性分析[J].地震研究,1995,18(3):252-257.
[6]蔡静观.波速比计算中的不确定因素和在地震预报中的应用[J].地震研究,2000,23(1):51-56.
[7]吕坚,高建华,赵爱平,等.九江-瑞昌5.7级地震序列重新定位与震源机制解[J].防灾减灾工程学报,2006,26(增刊):83-87.
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